How much deeper could we dig signals out of the noise if we sampled 32bit samples at 32 mega samples per second then piped it all over ip for the entirety of TACC to chew on. (Wiki lists TACC as 5th in the top 500)
Eric
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On Feb 9, 2021, at 6:02 AM, pete M via 44Net 44net@mailman.ampr.org wrote: There is always multiple ways to skin a cat. But the SDR I talk about is a transceiver. I know we can use other type of processing and less BW. But what is the fun?
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From: 44Net 44net-bounces+petem001=hotmail.com@mailman.ampr.org on behalf of Cliff Sojourner via 44Net 44net@mailman.ampr.org Sent: Monday, February 8, 2021 6:01:48 PM To: 44Net general discussion 44net@mailman.ampr.org Cc: Cliff Sojourner cls@employees.org Subject: Re: [44net] ASN # and Network Service Provider (NSP)
We already have hundreds of SDRs available via IP. One aggregation is at http://websdr.org/
Frankly, sending 50MHz bandwidth at say 16 bits over IP is perhaps the worst way to do it... Just to find that elusive 50Hz CW signal!??
The latest SDRs have a massive A/D for baseband capture, perhaps 250MHz, immediately processed by multiple FPGAs, then perhaps sent to Gnu Radio on a very fast multicore CPU. This is no simple trick. But my point is, people smarter than me have figured out it is better to decimate and process locally, not at the end of an IP connection.
So i am still at a loss for compelling high bandwidth applications.
(Thanks for indulging my detour here. Back to regularly scheduled BGP etc.)
Cliff K6CLS CM87
On February 6, 2021 3:54:12 PM PST, Tony Langdon via 44Net 44net@mailman.ampr.org wrote:
On 7/2/21 8:32 am, pete M via 44Net wrote: We dont have high bandwith application? What about 50 Mb/s ? is that high speed enough? SDR kike the Hermes-Liet 2.0 can feed the HF spectrum to a software
remotely By IP stream at up to 50Mb/s
Would it be a nice thing to have multiple SDR transceiver on multiple
bands all over the world available to ham that run a 44net adress? Now that would be neat - having access to SDR IFs remotely, though those speeds are only going to be available at a regional level if routing over the Internet. While I have 80+ Mbps available downstream, that really only applies to relatively local (within VK for me) endpoints. Once I'm going overseas, usable bandwidth can drop to 10 Mbps or less, from end to end. But the 2-2.4 MHz bandwidth of RTL-SDR class devices might be more practical on an international scale, which means a transport that can scale to suit available bandwidth. Also, for latency reasons, we would want optimal routing on our core infrastructure, which ties back to the previous discussion.
Nice out of the box thinking there. :)
Would it even be a nice intitative to build an high speed RF linking
system for that use case? The biggest challenge with high speed RF is cost and complexity. Not everyone is able to build UHF/microwave equipment reliably. I have a number of issues in that area - some intrinsic, some are time related, and the cost of high speed/wide bandwidth microwave equipment tends to be rather expensive, given that amateur applications tend to be low volume, compared to something like mobile phones or wifi.
I can think of many more project like that. Most people dont think of such project for a simple reason, most of
the mode we use are narrow by definition, and since the FCC limit the maximum Bandwith available by bands to a bare minimum and that the USA ham's must comply to this insane thing, the rest of the world is kind of being drag to that fact.
Just take the New pascket radio project, Canadian hams could use it
at the maximum spead it was designed for, US, nope 70cm bandwith limit will prevent it. Frustrating I must say. I'm pretty sick to death of being held back by archaic US regulations. Here, we can also use whatever bandwidth a mode requires, provided we stay within the band limits (on VHF and up). There may be some interesting band plan issues on 70cm, but we hams can resolve those. On 1.2 GHz and up, there's bandwidth to burn, and it would be good to make use of that. :) Maybe the rest of the world should just get on with it and encourage US hams to lobby to get their regulations updated to match the rest of the world, and in the meantime, the US battles on as best it can until they can sort out their regs and join us RF wise.
-- 73 de Tony VK3JED/VK3IRL http://vkradio.com
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